The present invention relates to a light projector device for projecting tests on a screen. More particularly, the invention relates to a device for projecting eyesight examination tests, such as visual acuity and astigmatism tests.
The device is of the kind comprising two discs interposed successively in the light beam of a light projection unit, each of the said discs being mounted for rotation, under the control of a separate motor, about an axis situated at a distance from the axis of the light beam of the said projection unit, one of the discs, known as the test disc, carrying circularly on a ring a series of translucent areas carrying tests and the other, known as the mask disc, carrying a succession of light passages, such as apertures, transparent or other areas, capable of being individually superimposed on all or part of the test areas of the test disc in the said light beam, and a test carrier dial mounted for rotation separately and adapted to turn in the light beam of the projection unit about an axis which is substantially that of the said light beam, that is to say about an axis which is substantially the optical axis of the projection unit.
As a rule, when tests for the examination of sight are concerned, the tests carried by the translucent areas of the test disc are visual acuity tests, while those carried by the rotating dial are astigmatism tests. Other tests can also be carried out with such a device.